In Memory Of
Christopher Reeves
1952-2004
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With my Uncle Stan KG4UBG, I
just recently built a Dual band 2m / 70cm Copper Cactus. One of my Ham
Friends, Mark Keefer N3JNC emailed me blueprints for this antenna
click here to view his
website
This Copper Cactus is made from 1/2 inch copper pipe and is easy to make. The only skill you need to build this antenna is to be able to solder copper pipe and some coax. Currently I am using one for my base antenna. I get a SWR reading of 1.5:1 on 2 meters & 1.7:1 on bottom end of 440 & 1.5:1 on the top end of the 440 band, which anything below a 2:1 is good. Ideally, you want a reading of 1:1 which is not very easy to get meaning that there is allot of tweaking involved.
Below you will find the blueprints I mainly used to construct the antenna, the only difference between my antenna and the prints in how the coax is attached but the center conductor & shield are solders to the same places. For more information view my building pictures click here.
Here are some measurements for the other VHF/UHF Bands. These measurements as courtesy of http://archimedes.galilei.com/raiar/cactus.html.
| Frequency | 52 MHz | 146 MHz | 223.5 MHz | 435 MHz | 912 MHz | 1265 MHz |
| Pipe Diameter | 1" | 3/4" | 1/2" | 1/2" | 3/8" | 3/8" |
| Stub | 54.70" | 19.36" | 12.65" | 6.46" | 3.02" | 2.16" |
| Overall Length | 163.92" | 58.09" | 37.94" | 19.39" | 9.07" | 6.49" |
| Separation | 5" | 2" | 1 1/4" | 3/4" | 1/2" | 1/4" |
| Connect At | 6" | 2 1/4" | 1 1/2" | 1" | 3/4" | 1/2" |
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IV Copyright ©2004 All Rights Reserved Page Last updated : 02/20/2005 12:31:50 AM |